


Running in Red Maze

by Imakebadfanfic (8oni)



Category: Undertale (Video Game)
Genre: F/M, Reader-Insert, Underfell Sans
Language: English
Status: Completed
Published: 2016-02-13
Updated: 2016-02-23
Packaged: 2018-05-20 05:25:19
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Rape/Non-Con
Chapters: 2
Words: 4,249
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5993098
Author URL: https://archiveofourown.org/users/8oni/pseuds/Imakebadfanfic
Summary: <blockquote class="userstuff">
              <p>You wake up and find yourself tied to the chair. Your first reaction is panic. You try to move your body but your arm and leg have been tied really tight you can’t move an inch. You look around and see that you are sitting in the middle of the room. The only light source is from above you, it only give you enough to see 1 meter in front of you so you can’t see anything else but you are sure you can feels something moving in the darkness.</p><p>Something that isn’t friendly.</p>
            </blockquote>





	1. Chapter 1

You wake up and find yourself tied to the chair. Your first reaction is panic. You try to move your body but your arm and leg have been tied really tight you can’t move an inch. You look around and see that you are sitting in the middle of the room. The only light source is from above you, it only give you enough to see 1 meter in front of you so you can’t see anything else but you are sure you can feels something moving in the darkness.

Something that isn’t friendly.

Your body get tense when you realized that whoever or _whatever_ it is that in the same room with you have start to move towards you.

At first you only see a small red light. Then as it getting closer you realized that it’s an eye. And before long you find yourself face to face with a skeleton.

A skeleton with a glowing left eye and empty right eye socket. It’s already intimidating but what makes it worse is the grin. It grin is really wide and his teeth looks sharp like a shark teeth and you can’t help but noticed that it have one gold tooth on it.

You feel that if you didn’t get tied tightly to the chair you would already falls to the floor because you can feel your leg shaking.

You have heard a rumor about a monster roaming the street on your city but you just dismiss it as a baseless rumor. But now you regret you didn’t believe on it. At least you will buy a pepper spray and bring it with you when you go out tonight. But seeing you can’t even move your arm you doubt a pepper spray will help you much.

The skeleton move its hand forward and you close your eyes, preparing for the worst when suddenly you feel the pressure on your body and leg is gone.

You open your eyes and see nothing. And you can move now.

Not sure what just happen, you stand up from the chair when your eyes are blinded by a strong light. It took some time for your eyes to readjust and then you see that you are in a HUGE room with a lot of container on it. They are arranged so they look like a maze and you can see from your standing point that there are 2 paths that you can choose.

You try to remember where that skeleton from before came from but you can’t decide so you just go with your gut and choose the closest path to you.

The container feels cold when you touch them while you walking along the path. You want to run but your leg still feels weak so you just walk slowly, trying to get out from the place.

You wish you have your phone with you so you can call for helps but you remember that you put it on your bag because they are too big to carry around and you can’t fit it on your pocket.

Right, you immediately remember that you drop your bag along with your phone when someone suddenly grab you from behind and you remember before you lose consciousness that your phone falls on the ground and make a loud sounds.

You grimace at that memory, even if you manage to get your phone back they probably will be broken by now.

You may have walk for 15 minute when you start hear that sounds.

It sounds like someone scratching on the steel, its high pitched and unpleased on ear.

And you noticed that the sound is getting closer.

You run. You run as fast as you can. The scenery getting blurry and you start to panic. There is only red and red container everywhere you run. You aren’t sure anymore if you are getting toward the exit or if you just running around in circle.

Then you see some red light in front of you and the next thing you know you crash on something hard and you fall on the ground.

Only that you didn’t exactly falls on ground but on top of something else.

You feel slightly dizzy and out of reflex your hands grip on the first things that you can find.

Only after a moment you realized that you are holding on something that feels like a bone.  A rib bone actually.

You froze. You look down and see a red t-shirt under your hands. You look up and you saw the skeleton from before staring at you.

It still has the same wide grin but it now give you a different looks. Like it’s unsure what to do and it is weighing it option.

You feel a chill on your back. You feel you won’t like whatever will come next so you start to push yourself up...

...only to get crushed by an invisible force. And the same force is pulling you up and you find yourself face to face again with the skeleton.

Only this time the skeleton is opening its mouth and you see something resembling a tongue slipping out from it. Except that it’s long and glowing in red color.

And it entering your mouth before you can even progress what happens.

It took a moment for you to realize that you have been kissed by a skeleton.

And you never have any kiss like that before.  

The kiss last for a while when you start feelings something hit you in your lower area. Something that doesn’t exist before.

That is when you snap back to reality and try to pull yourself away ...

...just to get yourself floating and slammed to the container.

Your back hurts and you feel dizzy again. But before you can even catch your breath your mouth have been filled with the same tongue from before.

You feels a boney fingers grab your naked ass –where did your pants go?- and lift your leg.

Then you feel something entering you.

And it hurts. But your scream got muffled and you can’t even move your hands, the invisible force keeps them on your side.

Finally he [at this points you just start call the skeleton with male pronouns and not it anymore] stop kissing you; you just manage to get some air when you feels something sharp on your shoulder.

Instead of screaming though you let out a moan, it just feels good and you noticed that you are getting wet and now it doesn’t hurt that much anymore.

He seems to know that because he is moving harder and faster and with each thrust you feel yourself closer to coming.

Then the dizziness takes over and you fainted.

 

When you wake up you are on your own beds. You try to get up when you feels your back, your head, your shoulder and every other place in your body hurts. Even your ass feels sore.

You lay down on your bed again when you saw something on your bedside table. You reach your hand and grab it. It’s a medicine with a paper attached on it, written there is

‘Get well soon. I am not done yet’


	2. His POV

**Summary for the Chapter:**

> Same story but from UF!San's POV.

Sans hate the city. The air, the human, the other monster that keep making fun of him even when they already in Surface, his brother -the Royal Guard’s captain-, and everything else. After years they finally get their longtime dream, to get back to the Surface but instead of full scale war like they are promised too, Asgore tell them to go hiding and wait for the right time.

And after 2 months hiding, Sans get enough of it and now here he is, watching humans from some dark alley. He can hear Papyrus yelling at him at his heads -‘SANS WHAT ARE YOU DOING GET BACK IMMEDIATELY AND REPORT TO ME’ and he just frown deeper at his own thought.

Oh he love Papyrus -even if he force Sans to call him the Great Terrible Papyrus all the time, especially when they aren’t alone-, he will never forget –and he can’t forget, because it seems everyone love to remind him- that if not for Papyrus who raise him ever since their parents gone -who are they, what is their name, what did they do for living, Sans never know, Papyrus only stare at him and tell him it’s not his business when he ask Papyrus when he is a kid and after Papyrus kick him in the stomach for asking again he never ask anymore- he probably already kick the dust, literally.

Sans have no idea why he born with only 1 hp, and in the Underground where everyone love to kill each other because they love to increase their _love_ , Sans is really lucky he is still alive until today.

Granted he is actually strong, but if he use his power he get tired really easily so that is why unless really necessary he never go all out and since his brother, the Great Terrible Papyrus, is a Royal Guard’s Captain no one seems to dare to touch him.

They love to talk behind his back though. And he can do nothing but let them be, because he knows he can’t kill them all.

‘Never start a fight you can’t win’ is one of things that Papyrus teaches him. He also teach Sans a lot of other things and now Sans have 10 hp, ability to dodge almost any attack –from the training with Papyrus wherever he have spare time- and job as Sentry.

People still say if not for Papyrus he will never get the job though -even if Sans manage to beat the old Sentry by his own magic- and there is even rumor that say that Papyrus do something to weaken the Sentry before he go fight Sans in duel for the job.

_Yeah right, like the Great Terrible Papyrus do care about me like that_

Is what Sans tell to himself when he heard the rumor. But he shut his mouth and says nothing to Papyrus or anyone else and after a while the rumor is dead.

Sans wish the one who spread it is dead too.

Sans is distracted from his own thought when he heard chatter from the bar near him. He can hear a cheerful female voice yelling

‘Oh come on stop that, there is no such thing as monster! You all just want to scare me since I live alone’

Sans feels his anger boiling inside of him

_Monster is real, human. And you are about to meet one_

-***-

Sans looking at the human body in his hands. Now he have gone and done it. He waited for hours until the human come out from the bar to grab them to his hiding place and scare them. Sans didn’t know they would be this fragile though. He just uses his magic lightly to ensure they won’t scream -before he wants them to- but they ended up knocked out in his arm.

There is no fun killing unconsciousness person. Sans isn’t a coward -even if everyone tell him that when he refuse to fight them back, he knows they wouldn’t try to kill him for real that is why he ignore them- and he wants the human to know that when he kills them, slowly and painfully.

It took seconds for Sans to decide before he vanished. He didn’t know that there is a glowing red eyes looking at him all this time and that the owner of the eyes is walking out from their hiding places and grab the stuff -that he leaving behinds- on the ground.

-***-

Sans look down at the human –that now has been tied nicely on the chair- and feels satisfied. Now they won’t be able to run away even if they want to. He has wanted to do this for a long time. Kidnapped someone, tie them on chair and then slowly torture them. But considering how fragile this human is, he decides to torture them mentally.

He looks to his surroundings. They are in a really HUGE room that has a lot container on it. This has been Sans favorite place since they come to the Surface. The place is abandoned and no one ever comes to this place, so Sans took this as his own place and after a lot works the place is now looks better.

He then teleport to the second floor and watching the red maze that he have been proudly make in all his spare time. He spends an hour’s paint all the container that he can found in red color. He didn’t know why he do that, he just feels like it. And he likes the color. Seeing anything in red color for some reason makes he feels calm.

And in the middle of the room, inside the maze that he have made, sitting the human that he have tied in the chair.

_Now just wait for them to wake up._

Sans grab the nearest mustard near him and start drink it down.

-***-

Sans already on his 3rd bottle but the human didn’t wake up yet. Sans start feels bored. His anger has gone and now he feels stupid.

_Maybe I should just dump the human somewhere before they wake up._

But before Sans can move, a purse suddenly show up in front of his face.

Sans nearly spitted out the mustard.

_Shit!_

He shocks his heads to his right and found a hand holding the purse.

A skeleton hands.

Sans immediately straighten his posture.

‘Bro... The Great Terrible Papyrus! What are you doing here?’

‘Fixing your mistake’

Sans feels a chill on his back

‘You know that there is no contact with humans, not until Asgore tell us to. And yet here you are, kidnapping a human. Do you know what kind of trouble you can get us into?’

‘...’

‘Fortunately it’s I, the Great Terrible Papyrus who found you. If it’s someone else...’

Papyrus red eyes start glowing. Sans understood what that means. If it is other monster who found him, he might have to kill them before they kill him first. Asgore have given his order of not touching human at all, unless until he tell the otherwise. And not many follow that, which is why Papyrus and the other Royal Guard have been actively patrolling to make sure no monster break the rule. Also why Sans have been left alone for a lot time he can sneak up and finish his own secret lair.

But because they are brother, because he is the younger brother of The Great Terrible Papyrus he can get away with him breaking the rule. Sans grit his teeth, he hate being treated like this, he hate feelings specials because that makes him feels a hope, that Papyrus do love him like he love him. As a brother. But he knows better.

‘Sans’

It’s that tone. The soft sweet tone that Papyrus always use to him after he scold him ever since he is a kid.

‘I understood. I will fix this’

‘Good. I know I can count on you’

And with that, Papyrus disappeared. Leaving the purse on the ground.

Sans just stare at the purse, he can still hear Papyrus last word

‘I know I can count on you’

Sans feels angry again but this time he didn’t know why.

And at those moments, he can feel the human moving.

_About time, human._

-***-

Sans is waiting in the darkness. He have staring at the humans for some time, the only light in the room is from their head so he can see them easily from where he stands, and watch every movement they make. Finally their eyes open and they start to look around them. Sans waiting until they try to move their body

_Let them know they are powerless_

Before he walk slowly towards them, he makes sure to spread his magic all around so the human can feels his presence, and then he stops in front of them.

He expected to hear screams anytime but the human just staring at him.

_... Huh, that’s new._

When human falls in Underground, they usually didn’t stay alive long enough for Sans to ever meet one. The crazy goat lady in Ruins usually kills them fast. And when there is one, they usually get delivered to Asgore ASAP. His brother makes sure of it.

When they get to surface and holed up in their base, Sans and the other monster spend most of their times watching an old movie, playing card, try not to stare at each other too long so not to trigger any murderous intent and eventually share the story when they manage to scare humans in Surface.

No direct contact is allowed sure but doesn’t means they can’t scare humans using magic. Napstablook have a blast. Since he is a ghost so naturally most humans can’t see him so all he needs to do is hide his presence and move stuff.

That is how Napstablook manage to get a nice suite all for himself in the highest apartment floor in central city.

Soon other monster tries what Napstablook do and before long anyone have a story to brag. Not Sans of course, he never a social type but he can’t help but listening when everyone brag about how they make the humans scream just from seeing their stuff floating around and being moved or when they feels something in the rooms with them and when the monster touch their leg...

_Well, not like it matters. I will make you scream later._

Sans move his hands closer and the human shut their eyes.

_... Can’t touch them, they might pass out again._

So Sans use his magic and remove the rope and then he teleport to the switch where he then turn on the light.

Sans then move back to the second floors and watching the humans slowly get up and start to walk in his red maze.

_They really walk slow..._

Sans think it might be 15 minutes since the human start walking but they only manage to walk a little, they are staggering and they are touching the container when they walk as if they are afraid to falls if they don’t do that.

_Not so cheerful anymore huh now you have seen that monster is real?_

Sans remember the human voice from the bar. He wants to hear the same voice again but this time filled with despair and fear.

Sans emptying the mustard in one go and grab the crowbar that he has prepared.

_Time to make some noise_

Sans teleport to the other side of the container that the human is holding and start scratching the wall with the crowbar. The high pitched voice is echoing across the room and Sans glad he didn’t have an ear or he might lose it.

Before long he can hear the human start running and Sans stop.

He has to muster his willpower to not laugh.

_Those guys sure have a nice trick._

He teleport back to 2nd floor where he casually lean on the fence and watch the human running frantically looking for a way out.

_I will miss this when I return you back to your home, human_

Sans have known the human’s name and their address. From the purse that Papyrus delivers to him. He has plan to teleport the human back to their home after he is done with them. He won’t kill them –not anymore-, he just want to hear them scream and then he will be satisfied.  

Sans straighten his pose and start looking at one specific point. He plans to teleport there and waiting for the humans to show up. If he suddenly shows up he is sure he will hear them scream.

But Sans didn’t expect the human to crash into him and knock both of them down on the ground.

Not to mention the fact that when they fall together, the human is now positioned above him and they are _gripping_ his rib bone.

His rib bone.

The most sensitive part of his body.

Sans have got a lot monster try to kill him and most know to go straight to the chest, where his soul is stored, since he feels nothing even if someone stab him in his eye socket. And that’s why Sans –and Papyrus- have training hard to keep anyone or anything touch them at all on their chest and yet this fragile human who pass out when he simply use his magic have manage to do something that no other monster –or human- able to do.

Sans flinch

For the first time Sans realized how soft the human body is. And that he didn’t hate the touch.

He can feel the humans mouth moving on his shirt. Their breathing is uneven and it feels hot in his bone.

And now he feels hot too.

And funny.

The human tighten their grip on his rib bone.

Sans grit his teeth.

He knows he should push the human away; it’s easy he doesn’t even have to use his magic, but he can’t move.

He can’t think.

_What did you do to me, human?_

He can feel the human shifted their body –they let go of his rib bone- and feels their gaze on him.

He wants them to scream.

If they scream he can get mad.

If he gets mad he can _force_ himself to push them away.

But instead of screaming, they just look at him with their half closed eyes –Sans didn’t know that it is because they are still dizzy from the crash- and their mouth open slightly.

And Sans can’t stop staring at their mouth.

Then their expression change and Sans didn’t care anymore.

_I don’t want them to scream._

Because he didn’t want to change his mind.

Sans use his magic and force the human to look at him in the face and then he kisses them.

To his surprise their mouth feels soft unlike any monster that he has kissed before –not like there are many- and it tasted like salt and fries. He continues exploring the inside of the human mouth, he licking their teeth and playing with their tongue. And soon he find himself wanting more.

_Shit. What have you done to me?_

The human didn’t seem to hate being kissed by him, he can feel their hands gripping on his rib bone again and that just add the heat on him.

Sans closed his eyes and concentrating his magic to his lower body part. He can feel the human shifting again when they realized the gravity of the situations.

_Too late for that, sweetheart._

He lifts them with his magic and slams them to the container. It makes a loud sound and Sans will worried about the humans –they are fragile after all- if his mind didn’t get clouded by now. He just can’t think. He walks where they are now pressed to the metallic red wall and before long he already in front of them.

He touches their short and removes it using his magic. He does the same to their underwear. He stare at their private part for a while – _so they have hair down there huh, interesting_ but Sans didn’t care much about human anatomy for now- before he kiss them again and then he lift their legs and put himself inside.

_Fuck. It’s so tight._

He move himself slowly before he noticed the tears on her eyes –at this point Sans start to call the human ‘her’ without realizing it- and he start to panic

_Shit. Shit. Oh shit._

Of course she is crying, he is hurting her. He totally forget that human is fragile and yet he is entering her dry like that.

Sans didn’t think twice before he release his mouth and then he bite her, putting his magic on her blood stream.

And it works. Because Sans can feels himself slip easily into her. And he can hear her moaning. Take that as a clue, Sans start to thrust deeper and faster, unaware that he have bitten too deep in his panic. He didn’t realized that her blood start to staining her clothes and that her breath starts to uneven.

It just after she goes limp Sans realized something is wrong.

_What? Who pass out when they have a sex?_

Sans staring at her before he realized the blood on her clothes and he cursing himself for that.

_Right, blood. Humans bleed unlike monster._

Sans feels frustrated, he is still inside her but he pull himself out, there is no way he can continue this when she didn’t even know what he do to her.

Sans rip out her clothes and start lick the wound to stop the bleeding.

 He then throws her over his shoulder and teleport to grab his purse before teleport again to her house.

-***-

Sans looking down at ____, her breathing is normal again. Sans do his best to heal her as much as he can but he never good at healing magic. He took out the medicine that he have taken from her medicine cabinets and put it on her bedside table.

Then he teleport back to his hiding place –because he need to clean stuff- but before that Sans make a rare genuine smile.

_Maybe this city isn’t so bad after all._

 

**Notes for the Chapter:**

> Well I hope you guys like it. And no if you guys think that UF!Sans is smiling because he is developing a romantic feelings on reader-chan. No, he is smiling because of the 'letter', he is a sadist and he is happy thinking that he can still scare poor reader-chan after this. 
> 
> Seriously I have no idea why I write this chapter, this is supposed to be a one shot. Well, thanks for reading!

**Author's Note:**

> Happy Valentine's Day!


End file.
